Enzyme histochemistry of glutamate dehydrogenase in ageing rat cerebellar cortex

The influence of ageing on glutamate dehydrogenase activity was studied in the cerebellar cortex of 3-month-old (young), 12-month-old (adult) and 26-month-old (aged) male Sprague-Dawley rats by using an enzyme histochemical technique. In young rats the enzyme reactivity was observed in the neuropil of the molecular layer as well as in the perikarya of basket cells and of stellate cells; within the cytoplasm of Purkinje neurons and in synaptic glomeruli of the granular layer. Glutamate dehydrogenase activity was significantly increased in the cerebellar cortex of adult rats and decreased in old animals. The synaptic glomeruli of the granular layer were the structures of the cerebellar cortex more remarkably affected by age-related changes. The possibility that decreased glutamate catabolism occurring in the ageing cerebellar cortex may result in an excess of the amino acid and may contribute to the nerve cell loss occurring in the cerebellum of old rats is discussed.